Radisson Sky City or Clarion are both within the terminal buildings. Clarion has much more amenities with nice outdoor pool, sauna, top floor restaurant etc. Note there is another Radisson a 5 minute bus ride from all terminals. Sweden still in partial holiday mode so I’m sure overnight rate plus late check out until 4pm would be possible. If all you want is a bed then Rest&Fly is also in the terminals, is cheaper and provides decent beds albeit with no room windows.
I wrote about Rest&Fly. He said he wants to sleep. Why would he want to spend time taking the bus to Jumbo hostel and then get to sleep at a time when most people will be checking out, walking around etc and the sound reverberates?!